The present invention relates to a method for positioning and supporting mobile or modular building constructions. More particularly, the invention relates to a structural foundation system including multiple supporting stanchions, or support piers, permanently embedded in preformed, level, concrete footings.
Numerous methods have been used in the past to place or position prefabricated mobile homes or other modular constructions on a prepared foundation, either temporary or permanent. Traditionally, xe2x80x9cmobilexe2x80x9d factory-built constructions have been merely placed on blocks, such as stacks of loosely placed concrete blocks. Since such supporting techniques involve no lateral support to resist loads such as wind or earthquake, various types of tie-downs or anchoring systems have been employed over the years.
As evidenced by damage statistics, prefabricated constructions suffer tremendous damage as a result of the overturning forces of high winds despite the fact that they have been tied down or anchored. Further, even when firmly installed, these conventional systems become loose over time due to repetitive tugging caused by the wind, and thus lose their effectiveness.
There are known in the art numerous more sophisticated support systems that have been conceived to address the above problems. However, these systems are quite expensive and labor intensive in their installation. For example, there are known supporting systems involving screw-jack arrangements, telescoping multi-sectional piers, or a combination of these in conjunction with shim plates for leveling. Additionally, the systems known in the art require elaborate footing schemes that include embedded anchor bolts, base plates, and rods. Despite the complex nature of these systems, properly leveling the mobile or modular constructions is tedious and often impossible since each of the supporting piers must be individually adjusted.
There has also been developed a system and method for emplacing prefabricated constructions that involves moving a mobile or modular construction in position over a plurality of footing excavations, leveling the mobile or modular construction, and placing an unhardened material, such as concrete, in each of the footings around stanchions that extend downwardly from the support frame of the mobile or modular construction into the footing excavations. See my parent application Ser. No. 09/710,778. While this construction system is highly effective, implementation can be difficult. That is, the movement of a mobile or modular construction over a plurality of excavation footings can be tedious, time-consuming, and even dangerous, for if a wheel of the transport vehicle were to run into one of the footing excavations, the structure could become unstable and overturn. Personal injury, or death, of the installation personnel could also result.
The present invention relates to a unique method of constructing a foundation system for supporting mobile or modular constructions that is cost effective, easily and accurately installed, and that will better withstand the forces of nature. More particularly, the method of the present invention facilitates the efficient and safe movement of a mobile or modular construction over the foundation on which the construction will be supported. As used herein, xe2x80x9cprefabricated constructionsxe2x80x9d means structures, in whole or in part, that are pre-manufactured or prefabricated before being moved to the site of installation. Such structures include, but are not limited to, mobile homes, doublewide homes, manufactured housing, and commercial structures such as modular office spaces and classrooms. According to the method of the present invention, a pattern of footing excavations conforming to the support frame system of the mobile or modular construction is first dug. The overall dimensions of the excavations are determined by the bearing strength of the soil. A block of foam is next suspended in each of the excavations. The foam block is dimensioned so that its horizontal cross section is slightly larger than the horizontal cross-section of the stanchion that it will support. The height of the foam block is less than the depth of the footing excavation so that concrete will fill the volume below the block. Each foam block is suspended in the excavation with wires or small rods so that it will remain firmly in place during formation of the concrete footing. The foam blocks are dimensioned and suspended such that a specific depth of concrete will settle beneath each foam block. As will be appreciated, each excavation and foam block is surveyed so that the upper surfaces of the series of foam blocks are at the same elevation. This ensures that the mobile or modular construction will be level when installed without the need for additional, and tedious, leveling steps.
Once the foam blocks have been properly positioned, concrete, or other suitable unhardened load-bearing material, is poured into each excavation until the load-bearing material is even with the surface of each foam block. Since the foam blocks are initially suspended in the excavations, a desired level, e.g., about 6 inches of unhardened concrete will fill in below each foam block. For typical concrete mixtures, a curing time of approximately 7 days is required.
After the concrete has cured to the desired hardness, the blocks of foam are removed. As those skilled in the art will appreciate, removing a solid object that is surrounded by concrete is typically quite difficult, if not impossible. It has been found, however, that forming the blocks of a foam material solves this problem. Because typical foams are dissolved, or melted, when contacted by organic liquids or hydrocarbon solvents, such as gasoline and the like, a small quantity of such a liquid is poured onto the foam. As a result, the foam essentially dissolves, leaving an open volume the size of the original foam block, and without adversely affecting the quality of the concrete.
The mobile or modular structure is next moved into position over the prepared footings. Since the size of the openings in each footing, e.g., about 5 inches by about 7 inches, are small compared to the wheels of a conventional transport vehicle, the transport vehicle and mobile or modular structure can drive over the footings without danger of personal injury, equipment damage, or fear of damaging the footings. The present invention is used with a support system for mobile or modular constructions of the type having two or more longitudinally extending support frame members thereunder. Once the structure is in position and lifted, or jacked up, vertical stanchions are attached to the support frame members of the structure at spaced points corresponding to the previously prepared footings.
The order of certain steps of this method is not critical. For example, the mobile or modular construction may be initially moved into position over a plurality of footings, prepared as described above, and then jacked up. Stanchions are then attached to the supporting structure of the mobile or modular construction. Alternatively, the stanchions may be attached to the support members prior to moving the jacked up mobile or modular construction into position. In either case, the upper portions of the stanchions are attached to the support members of the mobile or modular structure using angles or other suitable fasteners. The mobile or modular construction is positioned over the prepared footings so that the footings are in substantial alignment with the support members of the mobile or modular structure. When all of the stanchions are attached, the mobile or modular construction is lowered so that the stanchions are resting in and supported by slots in the concrete footings. Where additional lateral support is desired, one or more cross braces may be attached between selected pairs of stanchions to provide an additional level of restraint against horizontal forces, such as wind.
These and other aspects of the present invention will become apparent to those skilled in the art after a reading of the following description of the preferred embodiment when considered with the drawings.